Turbomachines, such as aircraft engines and stationary gas turbines, normally have at least one compressor-side and/or one turbine-side guide vane row having a multiplicity of guide vanes. Together with an inner ring, the guide vane row forms what is generally referred to as a guide vane ring. To set optimal operating conditions, the guide vanes are thereby preferably pivotably mounted about the longitudinal axis thereof and may thereby assume different rotational positions. In this case, one also speaks of variable guide vanes.
In the radial direction, the inner ring preferably has a plurality of recesses, into each of which a disk of a guide vane is inserted. Positioning pins of the guide vanes, that can cooperate with a corresponding adjusting device on the outer casing, can be used for a radially outer mounting of the guide vanes, as well as for the actuation thereof. Disposed on inner ring is preferably a seal carrier that is provided with sealing elements or abradable coatings, which are located opposite the sealing ribs of the rotor.
During operation, air enters into the gap between the walls of the recesses in the inner ring and the vane disk inserted in each case, at the pressure side of the vane airfoil on the rear side (in the primary flow direction) of the inner ring, and emerges again at the suction side of the vane airfoil on the front side (in the primary flow direction) of the inner ring. The vortices formed by this leakage have a negative effect on the primary air flow and thus on the efficiency of the turbomachine.